Your struggle to get your son to eat sounds very frustrating.  This may be a phase that your son is going through in order to test his control, or it could be a medical issue.  Have you talked to your son€™s pediatrician?  If there is nothing medically wrong, most pediatricians will assure you that he will not starve and will choose to eat when ready or when he gets hungry enough.
Is it just at meal times that he won€™t eat, or does he refuse snacks as well?  If he is eating snacks without a fuss, you may want to consider cutting back on them so he will be more likely to eat at mealtime.
If this is a control issue, you can try offering him opportunities to exercise his control by giving him choices.  You could have several foods that he has to choose from when he wants to eat.  Perhaps he can even help prepare it.  Be sure to limit the choices and make sure they are healthy.  Sit down and eat with him so he enjoys the meal time.  If you don€™t already, you may want to give him choices about other things like what to wear, or what book he would like read to him.  These opportunities might help him feel like he has some control over things in his life.
Another option you could try would to be to use some sort of reward system for eating properly at meal times.  Things like sticker charts or other small rewards can be very reinforcing to kids his age and may work to increase good eating habits.
Hopefully this helps!  If you are concerned for his physical health, please consider setting up an appointment with his pediatrician to discuss your concerns.
Boys Town National Hotline
1-800-448-3000
-an Education.com partner